linux-cve-announce - CVE-2025-68802: drm/xe: Limit num_syncs to prevent oversized allocations

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Message-ID: <2026011308-CVE-2025-68802-a7f9@gregkh>
Date: Tue, 13 Jan 2026 16:29:28 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-68802: drm/xe: Limit num_syncs to prevent oversized allocations

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

drm/xe: Limit num_syncs to prevent oversized allocations

The exec and vm_bind ioctl allow userspace to specify an arbitrary
num_syncs value. Without bounds checking, a very large num_syncs
can force an excessively large allocation, leading to kernel warnings
from the page allocator as below.

Introduce DRM_XE_MAX_SYNCS (set to 1024) and reject any request
exceeding this limit.

"
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1217 at mm/page_alloc.c:5124 __alloc_frozen_pages_noprof+0x2f8/0x2180 mm/page_alloc.c:5124
...
Call Trace:
 <TASK>
 alloc_pages_mpol+0xe4/0x330 mm/mempolicy.c:2416
 ___kmalloc_large_node+0xd8/0x110 mm/slub.c:4317
 __kmalloc_large_node_noprof+0x18/0xe0 mm/slub.c:4348
 __do_kmalloc_node mm/slub.c:4364 [inline]
 __kmalloc_noprof+0x3d4/0x4b0 mm/slub.c:4388
 kmalloc_noprof include/linux/slab.h:909 [inline]
 kmalloc_array_noprof include/linux/slab.h:948 [inline]
 xe_exec_ioctl+0xa47/0x1e70 drivers/gpu/drm/xe/xe_exec.c:158
 drm_ioctl_kernel+0x1f1/0x3e0 drivers/gpu/drm/drm_ioctl.c:797
 drm_ioctl+0x5e7/0xc50 drivers/gpu/drm/drm_ioctl.c:894
 xe_drm_ioctl+0x10b/0x170 drivers/gpu/drm/xe/xe_device.c:224
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl fs/ioctl.c:584 [inline]
 __x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:584
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xbb/0x380 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
...
"

v2: Add "Reported-by" and Cc stable kernels.
v3: Change XE_MAX_SYNCS from 64 to 1024. (Matt & Ashutosh)
v4: s/XE_MAX_SYNCS/DRM_XE_MAX_SYNCS/ (Matt)
v5: Do the check at the top of the exec func. (Matt)

(cherry picked from commit b07bac9bd708ec468cd1b8a5fe70ae2ac9b0a11c)

The Linux kernel CVE team has assigned CVE-2025-68802 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 6.8 with commit dd08ebf6c3525a7ea2186e636df064ea47281987 and fixed in 6.12.64 with commit e281d1fd6903a081ef023c341145ae92258e38d2
	Issue introduced in 6.8 with commit dd08ebf6c3525a7ea2186e636df064ea47281987 and fixed in 6.18.3 with commit 1d200017f55f829b9e376093bd31dfbec92081de
	Issue introduced in 6.8 with commit dd08ebf6c3525a7ea2186e636df064ea47281987 and fixed in 6.19-rc2 with commit 8e461304009135270e9ccf2d7e2dfe29daec9b60

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-68802
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	drivers/gpu/drm/xe/xe_exec.c
	drivers/gpu/drm/xe/xe_vm.c
	include/uapi/drm/xe_drm.h


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/e281d1fd6903a081ef023c341145ae92258e38d2
	https://git.kernel.org/stable/c/1d200017f55f829b9e376093bd31dfbec92081de
	https://git.kernel.org/stable/c/8e461304009135270e9ccf2d7e2dfe29daec9b60